In this paper, transistor lasers (TLs) are used as an optical modulator for generation of ASK(Amplitude Shift Keying) and FSK (Frequency Shift Keying) optical signals. Our analysis is based on continuity equation, rate equations, and the theory of discontinuity of quasi-fermi level at the abrupt junction. Our simulation results indicate that, the specification of ASK and FSK optical signals, are affected by dynamical behavior of TL. Also our simulation results indicate that, the collector-emitter voltage amplitude should be small enough that the nonlinear properties of TLs do not destroy the modulated optical signals.